IS PLAVIX RIGHT FOR YOU?

A new genetic test identifies people who
likely won't benefit from taking Plavix, a
common anti-clotting drug, after having a
stent placed in an artery.

Plavix was the third-best-selling medication
in the United States last year with sales of
$4.9 billion.

The new test, developed by Quest
Diagnostics, uses a saliva sample to detect
four possible mutations to the gene CYP2C19.

Patients with a mutation could opt for
Effient, an alternate anti-clotting drug; try a
double dose of Plavix; or take the standard
Plavix dose while being monitored closely by
their doctors

Mapping the human genome opened the door to personalized medical therapies based on genetics, but most of the progress in this growing field has centered on fighting cancer.

Now, scientists are on the brink of unleashing a generation of genetic tests and treatments for a much wider array of conditions.

One of those advancements is being piloted at Scripps Green Hospital in La Jolla, where cardiologists have begun testing heart patients for variations of a particular gene before placing stents in their clogged arteries. Successful diagnosis means preventing more heart attacks and strokes.

People with one or more of four mutations to the gene CYP2C19 can't properly process the drug clopidogrel, also known by its brand name, Plavix.

The medicine, which prevents blood clots, was the third-best-selling drug in the United States last year with sales of $4.9 billion, according to the health research company IMS Health in Norwalk, Conn.

“This is significant news for medicine as well as health care costs,” said Edward Abrahams, executive director of the nonprofit Personalized Medicine Coalition in Washington, D.C. “ ... Getting it right the first time makes a lot of difference to people who suffer from blood clots.”

Doctors routinely prescribe Plavix to the 1.2 million Americans who get stents each year because in the few weeks after surgery, those patients are particularly vulnerable to potentially deadly clots.

But the drug doesn't work in a third of people of European descent and more than 40 percent of individuals of African and Asian descent, according to recent studies.

Patients taking Plavix who also have the genetic mutations face a 53 percent higher risk of dying from a heart attack or stroke compared with those without the gene variations, researchers reported in a January edition of
The New England Journal of Medicine.

People with the mutations have three options.

They can try Effient, a new anti-clotting drug that is metabolized differently than Plavix but could cause more bleeding. They could take a higher dose of Plavix, which appears to work in some cases. Or they could stick with the standard dose of Plavix while their physician closely monitors its effectiveness.

The global company Quest Diagnostics recently developed a saliva test to identify the mutations and launched the product through Scripps Health, which operates Scripps Green and four other hospitals in San Diego County.

Scripps Green's relative proximity to the Quest laboratory in San Juan Capistrano, where the tests are processed, made the collaboration attractive, said Dr. Jay Wohlgemuth, vice president of science and innovation for the company.